Pipe couplings of the above type are used for sealingly and tension-proof interconnecting pipe or connecting pipe with other equipment, eg. a valve in a pipeline. A typical application is in pipelines for water and gas supply. Pipes for this purpose are grouped according to the nominal diameter DN, but within the same nominal diameter pipes of different materials have different outer diameters. A plastic pipe of DN 100 thus has an outer diameter of 110 mm, a steel pipe has a diameter of 114 mm and a cast-iron pipe has an outer diameter of 118 mm. Pipe couplings of the present type enable the use of the same pipe coupling within a specific DN group.
GB 2 167 146 A discloses a pipe coupling of the above type, wherein a sealing ring and a gripping ring are clamped between the conical end face of a sleeve and a conical end face of a pressure ring to bring the sealing ring and the gripping ring into sealing and gripping engagement, respectively, with the outer face of the pipe. The pressure ring is shaped as an integrally formed, rigid ring.
Furthermore EP 0 794 378 B1, EP 1 138 999 A1 and EP 0 974 780 B1 all disclose a pipe coupling of the above type, in which a gripping and sealing ring is arranged between the conical end face of a sleeve flange and the conical face of a pressure ring. The gripping and sealing ring is forced into tight-gripping and sealing engagement with the outer surface of the pipe when the pressure ring is pulled towards the flange of the sleeve. The gripping and sealing ring is formed of a large number of wedged-shaped abutting elements. The pressure ring is an integrally formed, rigid ring. Particularly due to the large number of elements of the gripping and sealing ring, the pipe coupling is complex and expensive to manufacture.